The sad part is that I didn't see anything beyond the mention of the RA when making my post. I don't exactly condone the action of buying alcohol for minors, but I also don't condone long-term application of drinking age law that may-or-may-not be applicable. I believe that legal drinking for 18-year-olds could prevent some of the binge drinking tragedies we have today, but there's too many politics that get in the way of a study like that, or it's relevance.
Regardless, yeah... You should bribe the RA, just because you never know when it might be useful to have a favor, but not about the alcohol, you don't want anything to mess with your status as "enrolled" in the school.
That said, a dorm room would probably be one of the safest places for a minor to have alcohol: They live on the premises, have a supposedly responsible adult also living there that has met the resident in person, if there's a mess made, said person can leave without driving/clean themselves up/clean up the mess, and that's just skimming the idea. To me, it seems like it could even be a good place to teach responsible drinking, but that's not how things go, it seems.